Catalyst compositions for selective dimerization and  polymerization of ethylene

ABSTRACT

A catalyst composition comprises an inert hydrocarbon solvent, having dissolved therein a titanate of the formula Ti(OR) 4  wherein each R is the same or different, and is a hydrocarbon residue, and an organic aluminum compound, wherein a molar ratio of the organic aluminum compound and any alkene present in the catalyst composition is greater than one.

FIELD

Disclosed herein are catalyst systems and processes for the preparationof a polymer from an alkene, preferably a polyethene, or downstreamproducts thereof.

BACKGROUND

Polymers have for a long time been desirable substances in the chemicalindustry. Polyethene and its derivatives, including co-polymerscomprising ethene as one of the co-monomers are of particular commercialinterest. One route for the preparation of polymers is by catalysedpolymerisation of alkenes. The demand still remains in the state of theart for improved processes for the preparation of polymers from alkenes,especially for processes with long catalyst lifetimes, high specificity,and short induction times.

SUMMARY

A catalyst composition comprises: a titanate of the formula Ti(OR)₄wherein each R is the same or different, and is a hydrocarbon residue;an ether catalyst modifier, preferably tetrahydrofuran, and analuminoxane wherein the aluminoxane is a methyl aluminoxane, a modifiedmethyl aluminoxane, or a combination comprising at least one of theforegoing.

A process for the preparation of a downstream polymer product,comprising contacting an alkene with the catalyst composition accordingto any of the preceding claims under conditions effective to form apolymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a schematic process for producing polymer product inaccordance with one example of the presently disclosed subject matter.

FIG. 2 represents a schematic process for producing polymer product inaccordance with one example of the presently disclosed subject matter.

DETAILED DESCRIPTION

The present invention is generally based on the object of overcoming atleast one of the problems encountered in the state of the art inrelation to the polymerisation reaction of an alkene, preferably anα-olefin, more preferably ethene, to give a polymer or downstreamproducts derived therefrom.

More specifically, the present invention is further based on the objectof providing a catalyst system and a process for a reaction which has ahigh product specificity, short induction time and a high catalystlifetime.

Another object is to provide an efficient and sustainable polymer sourcefor producing downstream products and shaped bodies.

A contribution to achieving at least one of the above described objectsis made by the subject matter of the category forming claims of thepresent invention. A further contribution is made by the subject matterof the dependent claims of the present invention which representspecific embodiments of the present invention.

A contribution to achieving at least one of the above-mentioned objectsis made by a catalyst composition comprising the following catalystcomponents:

a. a titanate with the general formula Ti(OR)₄, wherein R is ahydrocarbon residue and each R can be the same as or different to theother R in the molecule;

b. an ether;

c. at least one or more selected from methyl aluminoxane and modifiedmethyl aluminoxane.

In some embodiments of the catalyst composition, constituent c. ismodified methyl aluminoxane.

In some embodiments of the catalyst composition, the modifiedaluminoxane is a copolymer comprising (MeAlO) as a first repeating unitand (RAlO) as a further repeating unit, wherein R is not methyl.

In some embodiments of the catalyst composition, the ratio between thenumber of first repeating units and the number of further repeatingunits is in the range from about 20:1 to about 1:1, preferably in therange from about 15:1 to about 5:1, more preferably in the range fromabout 12:1 to about 8:1.

In some embodiments of the catalyst composition, the catalystcomposition comprises a further aluminium compound distinct from themethyl aluminoxane c.

In some embodiments of the catalyst composition, the further aluminiumcompound has the general formula Al_(n)R_(3n), wherein n is 1 or 2, R isa hydrocarbon residue, H or a halogen, preferably a hydrocarbon residueor a halogen, more preferably an alkyl group or aryl group or halogen,most preferably an alkyl group or a halogen. In one aspect of thisembodiment, the further aluminium compound is selected from the groupconsisting of the following: AlH₃, AlEth₃Cl₃ and AlCl₃.

In some embodiments of the catalyst composition, the molar ratio betweenthe further aluminium compound and the total amount of methylaluminoxane and modified aluminoxane is in the range from about 1:5 toabout 5:1, preferably in the range from about 1:3 to about 3:1, morepreferably in the range from about 1:2 to about 2:1.

In some embodiments of the catalyst composition, the catalyst isdissolved in a liquid.

In some embodiments of the catalyst composition, the liquid is an alkaneor an alkene.

In some embodiments of the catalyst composition, the liquid is a C₆-C₁₂alkane or a C₆-C₁₂ alkene.

In some embodiments of the catalyst composition, the liquid is at leastone or more selected from the group consisting of butene, hexane,heptane, and octane.

In some embodiments of the catalyst composition, the titanate isTi(O-butyl)₄.

In some embodiments of the catalyst composition, the titanate isTi(O-n-alkyl)₄.

In some embodiments of the catalyst composition, the titanate isTi(O-n-butyl)₄.

In some embodiments of the catalyst composition, the ether istetrahydrofuran.

A contribution to achieving at least one of the above mentioned objectsis made by a process for the preparation of a polymer, wherein an alkenecomes into contact with a catalyst composition according to theinvention.

In embodiment of the process for the preparation of a polymer, thealkene in ethene.

In embodiment of the process for the preparation of a polymer, thepolymer is a polyethene.

In embodiment of the process for the preparation of a polymer, thealkene and the catalyst composition come into contact in a homogeneousliquid phase.

In embodiment of the process for the preparation of a polymer, at leastone or both of the following conditions is satisfied:

a. The pressure of the system is in the range from about 5 to about 50bar;

b. The temperature of the system is in the range from about 40 to about80° C.

A contribution to achieving at least one of the above mentioned objectsis made by a process for the preparation of a downstream productcomprising the following preparation steps:

i. preparation of a polymer according to the invention,

ii. reaction of the polymer to obtain the downstream product.

In embodiment of the process for the preparation of a downstreamproduct, the downstream product is converted into a shaped body.

A contribution to achieving at least one of the aforementioned objectsis made by a catalyst composition. Preferred catalyst compositions inthe context of this invention catalyse the reaction of an alkene,preferably ethene, to obtain a polymer, preferably a polyethene. It ispreferred that the catalyst composition contribute to favourableproperties of the reaction, preferably to improved catalyst activity,product selectivity of the required polymer, an increased catalystlifetime.

A preferred catalyst composition comprises a titanate, preferablytetra-n-butyl titanate; an ether catalyst modifier, preferablytetrahydrofuran; one or more selected from the group consisting methylaluminoxane, modified methyl aluminoxane, and a combination comprisingat least one of the foregoing. In some embodiments, the catalystcomposition comprises a further aluminium compound distinct from c.

Preferred titanates are compounds of the general formula Ti(OR)₄,wherein R stands for a hydrocarbon residue, preferably an alkyl group oran aryl group, more preferably an alkyl group, and each R in a moleculemay be the same as or different to the other R groups in the molecule.Titanates are known to the skilled person, and the specific titanate maybe selected in order to enhance the advantageous properties of theprocess. R is preferably a straight chain or branched alkyl group, morepreferably straight chain. R is preferably a C₂-C₁₂ alkyl group, morepreferably a C₂-C₈ alkyl group, most preferably a C₃-C₅ alkyl group. Thepreferred alkyl group is butyl, which includes n-butyl and iso-butyl.Suitable organic titanium compounds include, but are not limited to,tetraethyl titanate, tetraisopropyl titanate, titanium tetra-n-butoxide(TNBT), and tetra-2-ethylhexyl titanate. In some embodiments, theorganic titanium compound is titanium tetra-n-butoxide.

In some embodiments, the titanate can be present in high concentrationin the reaction mixture, for example in a concentration of about 0.0001to about 0.1 mol/dm³, about 0.0002 to about 0.01 mol/dm³, morepreferably about 0.0005 to about 0.001 mol/dm³.

It is preferred for the methyl aluminoxane and/or modified methylaluminoxane to act as catalyst activator. The skilled person hasknowledge of methyl aluminoxanes and he may select any methylaluminoxane and/or modified methyl aluminoxane which he considerssuitable for increasing favourable properties of the invention.Preferred methyl aluminoxanes are compounds with the general formula(CH₃AlO)_(n). Preferred modified methyl aluminoxanes are compounds withthe general formula (R_(a)(CH₃)_(b)AlO)_(n) wherein a in the range from0 to 1 and b is equal to 1-a, and wherein R is not methyl. Preferred Rgroups in this context are alkyl groups, preferably C₂-C₁₀ alkyl groups,more preferably octyl or butyl, most preferably butyl. It is preferredfor a to be in the range from about 0.01 to about 0.5, more preferablyin the range from about 0.02 to about 0.4, most preferably in the rangefrom about 0.03 to about 0.35.

The further organic aluminum compound is a compound of the formula AlR₃,wherein R stands for a hydrocarbon, hydrogen or a halogen, preferably ahydrocarbon or a halogen, more preferably alkyl or aryl or halogen, mostpreferably an alkyl group or halogen and each R in a molecule may be thesame as or different to the other R groups in the molecule. Aluminiumcompounds are known to the skilled person, wherein specific aluminiumcompounds are selected in order to enhance the advantageous propertiesof the process. R is preferably a straight chain or branched alkylgroup, more preferably straight chain. R is preferably a C₁-C₁₂ alkylgroup, more preferably a C₁-C₈ alkyl group, most preferably a C₁-C₄alkyl group. The preferred alkyl group is ethyl. Suitable organicaluminum compounds include, but are not limited to, triethylaluminum(TEAL), tripropylaluminum, triisobutylaluminum, diisobutylaluminumhydride, and trihexylaluminum. In some embodiments, the organic aluminumcompound is triethylaluminum.

In some embodiments, it is preferred for the catalyst composition tocomprise a catalyst modifier, in particular an amine catalyst modifieror an ether catalyst modifier. Such ether catalyst modifiers are known,and can act as a co-catalyst or catalyst modifiers to the titanate,preferably by coordination of the titanate with a lone pair ofelectrons. Such ether catalyst modifiers are well known to the skilledperson and he may select any ether which he considers to be appropriatein the context and preferably improving the favourable characteristicsof the reaction, preferably a reduced initiation time, increased yieldand reduced polymer fouling.

Preferred ether catalyst modifiers may be monoethers or polyethers.Preferred substituents of the ether are alkyl groups. Preferred alkylgroups are methyl, ethyl, propyl, n-butyl, iso-butyl, t-butyl, and otherhigher alkyl groups. Some preferred monoether catalyst modifiers aredimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, methylethyl ether, methyl propyl ether, methyl butyl ether, ethyl propylether, ethyl butyl ether, propyl butyl ether, tetrahydrofuran, ordihydropyran. The preferred mono ether is tetrahydrofuran.

Preferred polyether catalyst modifiers are 1,4 dioxane or ethers basedon polyalcohols, preferably glycols or glycerols, preferably ethyleneglycol. Preferred ethers based on glycol are dimethyl ethylene glycol,diethyl ethylene glycol, dipropyl ethylene glycol, dibutyl ethyleneglycol, methyl ethyl ethylene glycol, methyl propyl ethylene glycol,methyl butyl ethylene glycol, ethyl propyl ethylene glycol, ethyl butylethylene glycol, propyl butyl ethylene glycol.

In an embodiment an ether catalyst modifier is present, andtetrahydrofuran is preferred. In another embodiment, the catalystcomposition contains at least two or more ether catalyst modifiers,preferably with at least one or more, preferably all, as describedabove, preferably with one of the ethers being tetrahydrofuran.

The skilled person may modify the relative ratios of the components ofthe catalyst composition in order to increase the advantageousproperties of the reaction.

The catalyst composition may be present dissolved in a liquid,preferably an alkane, preferably hexane, preferably as a homogeneousliquid. In an aspect of this embodiment, the liquid is an alkane or analkene or an aromatic solvent. In a further aspect of this embodiment,the liquid is a C₄-C₁₂ alkane, preferably a C₄-C₈, more preferably aC₄-C₆ alkane; or a C₄-C₁₂ alkene, preferably a C₄-C₈ alkene, morepreferably a C₄-C₆ alkene. In a further aspect of this embodiment, theliquid is one or more selected from the group consisting of butene,hexane, heptane, and octane.

The catalyst composition may be pre-prepared or prepared in situ, andpreferably is pre-prepared.

When prepared in situ, the components of the catalyst composition areintroduced to the reaction system as two or more components that areadded sequentially.

In some embodiments, the titanate is pre-mixed with an ether catalystmodifier, optionally together with the catalyst additive. In an aspectof this embodiment, they are mixed in an inert solvent, preferably analkane, preferably one or more of the following: pentane, hexane,heptane, octane, nonane, or decane, preferably hexane.

In some embodiments, the titanate, the ether catalyst modifier, or acombination thereof, the aluminoxane, and the optional organic aluminumcompound are premixed, preferably in the absence of an olefin (alkene).In an aspect of this embodiment, they are mixed in an inert solvent,preferably an alkane, preferably one or more of pentane, hexane,heptane, octane, nonane, or decane, preferably hexane.

In other embodiments, the titanate, the ether catalyst modifier,aluminoxane, and the optional organic aluminium compound are premixed,preferably in the absence of olefin. In one aspect of this embodiment,they are mixed in an inert solvent, preferably an alkane, preferably oneor more selected from the group consisting of the following: pentane,hexane, heptane, octane, nonane, decane, preferably hexane. The catalystadditive can further be optionally mixed at the same time with thesecomponents in the inert solvent.

In some embodiments, no more than 10% of alkene is present in thepreparation of the catalyst compositions. Preferably, no alkene ispresent in any of the steps of the catalyst preparation. The catalystcomposition first comes into contact with alkene during the reaction forthe preparation of the α-olefin. In some embodiments, no polymer ispresent or created in the catalyst composition during its preparation.

In some embodiments, the catalyst composition is prepared shortly beforeuse in the preparation of an α-olefin. It is preferred for the preparedcatalyst system not be stored for longer than 1 week, preferably notlonger than 1 day, more preferably not longer than 5 hours before beingemployed as catalyst for the preparation of an α-olefin or otherreaction process.

In some embodiments, the catalyst composition is not activated untilshortly before being employed in the reaction. It is preferred that thealuminoxane and the optional organic aluminium compound not be broughtinto contact with the other catalyst components earlier than 30 minutes,preferably not earlier than 15 minutes, more preferably not earlier than10 minutes, most preferably not earlier than 5 minutes before thecatalyst composition is employed in the reaction.

In some embodiments it is preferred for the individual components to beprepared shortly before use. It is preferred that at least one or moreof the catalyst components not be stored for longer than 1 week,preferably not longer than 1 day, more preferably not longer than 5hours after its preparation and before being employed as a component ofthe catalyst for the reaction. In an aspect of this embodiment, thetitanate is not stored for longer than 1 week, preferably not longerthan 1 day, more preferably not longer than 5 hours after itspreparation and before being employed as a component of the catalyst inthe reaction. In an aspect of this embodiment, the organic aluminiumcompound is not stored for longer than 1 week, preferably not longerthan 1 day, more preferably not longer than 5 hours after itspreparation and before being employed as a component of the catalyst forthe reaction.

A contribution to achieving at least one of the above mentioned objectsis made by a reaction process for the preparation of a polymer from analkene, preferably a reaction process for preparation of a from a C₂-C₈alkene, most preferably a process for preparation of polyethene fromethene. In some embodiments of a process for the preparation of polymer,an alkene, preferably a C₂-C₈ alkene, most preferably ethene, comes intocontact with a catalyst composition as described above. The polymerincludes at least 2 repeat units based on the alkene. The alkene and thecatalyst may come into contact in a homogeneous liquid phase.

Preferred polymerisation reactions can be mono-polymerization (i.e.,homopolymerisation) reactions or copolymerization reactions, preferablycopolymerization reactions. The preferred homopolymerisation product ispolybutene. The preferred co-polymers comprise units derived from theα-olefin, preferably 1-butene, and one or more co-monomers such asethene, propene, pentene, styrene, acrylic acid, methacrylic acid,methyl acrylate, methyl methacrylate, acrylonitrile, methacrylonitrile,or vinyl chloride, preferably ethene. The preferred copolymer is acopolymer of ethene and 1-butene, preferably with a larger weightpercent (wt. %) of units derived from ethene monomers than of unitsderived from 1-butene monomers, preferably with a weight ratio of etheneunits to 1-butene units of about 50:1 to about 5:1, more preferablyabout 30:1 to about 10:1, most preferably about 25:1 to about 15:1. Theskilled person may vary the ratio relating the mass of ethene monomersand 1-butene monomers in order to achieve the desired properties of thecopolymers, such as crystallinity and elasticity.

In some embodiments, the reaction is carried out as a flow reaction. Inother embodiments, the reaction is carried out as a batch reaction. Itis preferred that the reaction proceed as a homogeneous liquid phasereaction.

FIG. 1 shows a schematic process diagram 100 for an example batchprocess in accordance with the presently disclosed subject matter. In101 the catalyst composition is prepared. In 102 the catalystcomposition and olefin, e.g., ethylene, are brought into contact in theliquid phase, e.g., in 1-butene as a solvent. In 103 the polymer productof the reaction, e.g., polyethene, is separated from the product mix.Optionally, the catalyst composition can be salvaged from the productmix. The catalyst composition can thus be recycled.

FIG. 2 shows a schematic process diagram 200 for an example flow processin accordance with the presently disclosed subject matter. In 201 thecatalyst composition is prepared and introduced into the reactionsystem, e.g., 1-butene solvent system. The catalyst compositioncomponents can either be premixed or added sequentially. In 202 thealkene, e.g., ethylene, is introduced into the reaction system. In 203the polymer product, e.g., polyethene, is removed from the reactionsystem.

The skilled person can select the solvent for the reaction process inorder to improve the advantageous properties of the reaction. Thesolvent for the reaction is preferably an alkane, an alkene, or anaromatic hydrocarbon. Preferred alkanes in this context are C₂-C₁₂alkanes, preferably C₄-C₈ alkanes, most preferably hexane, heptane, oroctane, including all isomers of each, and more preferably n-hexane.Preferred alkenes in this context are C₂-C₁₂ alkenes, preferably C₄-C₈alkenes, including all isomers of each, most preferably butene.Preferred aromatic hydrocarbons in this context are benzene, toluene,and phenol. In some embodiments, the solvent for the reaction isdifferent than the solvent employed for preparation of the catalystsystem.

The reaction can be performed at a temperature of from about 20° C. toabout 150° C., from about 40° C. to about 100° C., from about 20° C. toabout 70° C., from about 50° C. to about 70° C., from about 50° C. toabout 55° C., or from about 55° C. to about 65° C. In some embodiments,the reaction is performed at a temperature of about 60° C. The reactioncan be performed at a pressure of from about 5 bars to about 50 bars,from about 10 bars to about 40 bars, or from about 15 bars to about 30bars. In some embodiments, it is preferred that at least one of thefollowing conditions be satisfied during the reaction:

a. the pressure of the system is about 1 to about 50 bar, preferablyabout 5 to about 50 bar, more preferably about 10 to about 40 bar, mostpreferably in the range from about 15 to about 30 bar; or

b. the temperature of the system is about 30 to about 150° C.,preferably about 40 to about 100° C., more preferably about 50 to about70° C., most preferably about 55 to about 65° C.

In some embodiments, the reaction is conducted in a batch where aselected volume of the presently disclosed catalyst composition can beintroduced into a reactor provided with usual stirring and coolingsystems, and can be subjected therein to an ethylene pressure, which canbe from about 22 bars to about 27 bars. In some embodiments, thereaction using the presently disclosed catalyst composition is conductedat an ethylene pressure of about 23 bars. One of ordinary skill in theart can adjust the temperature, pressure and other conditions of thereaction in order to bring about favorable properties of the reaction,for example, in order to ensure that the reaction system is present as ahomogeneous liquid phase.

The above conditions are particularly preferred where the solvent forthe reaction is 1-butene, in order to ensure that the reaction system ispresent as a homogeneous liquid phase. Where other solvents are used,the skilled person may adjust the temperature, pressure and otherconditions of the reaction in order to bring about favourable propertiesof the reaction and in order to ensure that the reaction system ispresent as a homogeneous liquid phase. In some embodiments of theprocess, the alkene and the catalyst come into contact in a liquid phasecomprising at least 50 wt. % but-1-ene, based on the total weight of theliquid phase.

The reaction product may be extracted by any method which the skilledperson considers to suitable in the context. Preferred methods ofextraction include distillation, precipitation, crystallisation,membrane permeation, and the like.

In some embodiments, the polymers are further processed. In an aspect ofthis embodiment, this further processing preferably involves formationof shaped objects such as plastic parts for electronic devices,automobile parts, such as bumpers, dashboards, or other body parts,furniture, or other parts or merchandise, or for packaging, such asplastic bags, film, or containers.

The following examples are illustrative of the presently disclosedsubject matter and they should not be considered as limiting the scopeof the subject matter or claims.

EXAMPLES

The following test methods are applicable to the claims, and were usedin the Examples.

Polymer fouling was identified by visual inspection and by using a metalspatula to scrape the inside surfaces of the reactor followingcompletion of the reaction. Where polymer fouling occurs, a thin layerof polymer can be seen on the surfaces of the walls of the reactorand/or on the stirrer. The thin polymer layer is white is colour andincludes thin strands.

Initiation time was determined by monitoring the pressure in the reactoror the flow rate of the feed to the reactor. Once the reaction starts,ethene feed is consumed.

In a batch reactor, onset of reaction is manifested as a drop inabsolute pressure. Thus, pressure remains roughly constant during theinitiation period and starts to drop once the initiation period is over.The initiation time is the time spent at roughly constant pressure oncethe reactants and catalyst have been brought into contact and before thereaction starts.

In a continuous reactor, onset of reaction is manifest as an increase inthe flow rate of ethene entering the reactor. At constant pressure,there is roughly no flow of ethene into the reactor during theinitiation period. Ethene flows into the reactor once the initiationperiod is over. The initiation time is the time spent at roughly zeroflow rate once the reactants and catalyst have been brought into contactand before the reaction starts.

Example 1

Example 1 illustrates the catalyst system including a tetra-substitutedtitanate, a dibutyl ether, and trialkyl aluminium, and its use in aprocess for the preparation of an α-olefin from an alkene, in particularpreparation of 1-butene from ethene. The results are summarized in Table1.

Example 1a. The reaction is carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bar. Thistemperature and pressure ar maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mldibutyl ether (Aldrich) are introduced into 50 ml n-hexane (Aldrich). Tothis is added 1.8 ml 1M solution of triethyl aluminium in n-hexane. Thecatalyst system in hexane is introduced into the reactor. The reactionsystem is heated to 60° C. under stirring and pressured to 23 bar withethene for 1 hour. The product is collected in an adjacent vessel afterdepressurising.

Example 1b (comparative). Example 1a is repeated except with 0.25 mltetrahydrofuran in place of 0.25 ml dibutyl ether.

Example 1c. Example la is repeated except with a mixture of 0.125 mltetrahydrofuran and 0.125 ml dibutyl ether in place of 0.25 ml dibutylether.

TABLE 1 Dibutyl ether Example (ml) Tetrahydrofuran (ml) Yield Activationtime 1a 0.25 0 High Short 1b 0 0.25 Medium Medium 1c 0.125 0.125 Veryhigh Very short

Example 2

Example 2 illustrates the catalyst system comprising tetraalkyltitanate, a silicate, and trialkyl and its use in a process for thepreparation of an α-olefin from an alkene, in particular preparation of1-butene from ethene. The results are summarized in Table 2.

Example 2a. The reaction was carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bars. Thistemperature and pressure were maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mltetraethyl silicate (Aldrich) were introduced into 50 ml n-hexane(Aldrich). To this was added 1.8 ml 1M solution of triethyl aluminium inn-hexane. The catalyst system in hexane was introduced into the reactor.The reaction system was heated to 60° C. under stirring and pressured to23 bar with ethene for 1 hour. The product was collected in an adjacentvessel after depressurising. The yield of 1-butene, expressed as thepercentage based on full conversion of the introduced ethene, was 90%.No polymer fouling was observed.

Example 2b (comparative). Example 2a was repeated except with 9 mltetrahydrofuran in place of 25 ml tetraethyl silicate. The observedyield was <1%. Some polymer fouling was observed.

TABLE 2 Example Co-catalyst Yield Polymer fouling 2a Si(OCH₂CH₃)₄ 90% No2b Tetrahydrofuran <1% Yes

Example 3

Example 3 illustrates the catalyst system comprising a titanate, anether, a methyl aluminoxane, and optionally a second aluminum compound,and its use in a process for the preparation of an polymer from analkene, in particular preparation of polyethylene from ethene.

Example 3a. The reaction was carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bar. Thistemperature and pressure were maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mltetrahydrofuran (Aldrich) were introduced into 50 ml n-hexane (Aldrich).To this was added 1.8 ml 1M solution of methyl aluminoxane in n-heptane(MAO). The catalyst system in hexane was introduced into the reactor.The reaction system was heated to 60° C. under stirring and pressured to23 bar with ethene for 1 hour. The product was collected in an adjacentvessel after depressurising. The yield of polymer, expressed as thepercentage based on full conversion of the introduced ethene, was 95%.

Example 3b. Example 3a was repeated except that 1.8 ml 1M solution ofmodified methyl aluminoxane (CH₃)_(0.7)(iso-But)_(0.3) (MMAO) wasemployed in place of the methyl aluminoxane.

Example 3c. Example 3a was repeated except that a mixture of 0.9 ml 1Msolution of methyl aluminoxane and 0.9 ml 1M triethyl aluminium (TEAL)was employed in place of the methyl aluminoxane.

Example 3d. Example 3a was repeated except that a mixture of 0.9 ml 1Msolution of modified methyl aluminoxane (CH₃)_(0.7)(iso-But)_(0.3) and0.9 ml 1M triethyl aluminium was employed in place of the methylaluminoxane.

Example 3e (Comparative). Example 3a was repeated except that 1.8 ml 1Msolution of triethyl aluminium was employed in place of the methylaluminoxane.

The results are summarized in Table 3, where results are ranked on ascale of 1 to 5, with 1 being the least favourable and 5 being the mostfavourable.

TABLE 3 Example Activator Yield Initiation time Catalyst lifetime 3a MAO2 2 2 3b MMAO 3 3 3 3c MAO and TEAL 4 4 4 3d MMAO and TEAL 5 5 5 3e TEAL1 1 1

The invention is further illustrated by the following embodiments.

Embodiment 1. A catalyst composition, comprising: a titanate of theformula Ti(OR)₄ wherein each R is the same or different, and is ahydrocarbon residue; an ether catalyst modifier, preferablytetrahydrofuran; and an aluminoxane wherein the aluminoxane is a methylaluminoxane, a modified methyl aluminoxane, or a combination comprisingat least one of the foregoing.

Embodiment 2. The catalyst composition of any one or more of thepreceding embodiments, wherein the titanate is Ti(O-butyl)₄,Ti(O-n-alkyl)₄, Ti(O-n-butyl)₄, or a combination comprising at least oneof the foregoing;

Embodiment 3. The catalyst composition of any one or more of thepreceding embodiments, wherein the modified methyl aluminoxane is acopolymer comprising MeAlO repeating units and R³AlO repeating unitswherein R is a C₂-₁₂ hydrocarbon, preferably wherein a ratio of thenumber of MeAlO repeating units and the number of R³AlO repeating unitsis about 20:1 to about 1:1.

Embodiment 4. The catalyst composition of any one or more of thepreceding embodiments, comprising a further organic aluminium compounddistinct from the methyl aluminoxane and from the modified methylaluminoxane, preferably wherein a molar the ratio between thealuminoxane and the organic aluminium compound is about 1:5 to about5:1.

Embodiment 5. The catalyst composition of embodiment 4, wherein theorganic aluminium compound is of the formula Al_(n)R_(3n), wherein n is1 or 2 and each R is the same or different, and is hydrogen, ahydrocarbon residue, or halogen, preferably wherein the aluminiumcompound is triethyl aluminium.

Embodiment 6. A process for the preparation of a polymer, the processcomprising contacting an alkene with the catalyst composition accordingto any of the preceding embodiments under conditions effective to form apolymer.

Embodiment 7. The process according to embodiment 6, wherein the alkeneis ethene and the polymer is polyethylene.

Embodiment 8. The process according to embodiment 6 or 7, wherein thecontacting is in a homogeneous liquid phase.

Embodiment 9. The process according to any one or more of embodiments 6to 8, wherein the conditions include at least one of a pressure of about5 to about 50 bar, or a temperature of about 40 to about 80° C.

Embodiment 10. The process according to embodiment any one or more ofembodiments 6 to 9, further comprising shaping the polymer to provide anarticle.

The term “about” or “substantially” means within an acceptable errorrange for the particular value as determined by one of ordinary skill inthe art, which will depend in part on how the value is measured ordetermined, i.e., the limitations of the measurement system. Forexample, “about” can mean a range of up to 20%, up to 10%, up to 5%, andor up to 1% of a given value. The singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.“Or” means “and/or.” Unless defined otherwise, technical and scientificterms used herein have the same meaning as is commonly understood by oneof skill in the art to which this invention belongs. The endpoints ofall ranges directed to the same component or property are inclusive andindependently combinable (e.g., ranges of “less than or equal to 25 wt%, or 5 wt % to 20 wt %,” is inclusive of the endpoints and allintermediate values of the ranges of “5 wt % to 25 wt %,” etc.).Disclosure of a narrower range or more specific group in addition to abroader range is not a disclaimer of the broader range or larger group.

All publications, patents, and patent applications cited herein arehereby expressly incorporated by reference for all purposes to the sameextent as if each was so individually denoted.

Although the presently disclosed subject matter and its advantages havebeen described in detail, it should be understood that various changes,substitutions, and alterations can be made herein without departing fromthe spirit and scope of the presently disclosed subject matter asdefined by the appended claims. Moreover, the scope of the presentlydisclosed subject matter is not intended to be limited to the particularembodiments described in the specification. Accordingly, the appendedclaims are intended to include within their scope such modifications.

1. A catalyst composition, comprising: a titanate of the formula Ti(OR)₄ wherein each R is the same or different, and is a hydrocarbon residue; an ether catalyst modifier, and an aluminoxane wherein the aluminoxane is a methyl aluminoxane, a modified methyl aluminoxane, or a combination comprising at least one of the foregoing.
 2. The catalyst composition of claim 1, wherein the titanate is Ti(O-butyl)₄, Ti(O-n-alkyl)₄, Ti(O-n-butyl)₄ or a combination comprising at least one of the foregoing.
 3. The catalyst composition of claim 1, wherein the modified methyl aluminoxane is a copolymer comprising MeAlO repeating units and R³AlO repeating units wherein R³ is a C₂-₁₂ hydrocarbon.
 4. The catalyst composition of claim 1, comprising a further organic aluminium compound distinct from the methyl aluminoxane and from the modified methyl aluminoxane.
 5. The catalyst composition of claim 4, wherein the organic aluminium compound is of the formula Al_(n)R_(3n), wherein n is 1 or 2 and each R is the same or different, and is hydrogen, a hydrocarbon residue, or halogen.
 6. A process for the preparation of a polymer, the process comprising contacting an alkene with the catalyst composition according to claim 1 under conditions effective to form a polymer.
 7. The process according to claim 6, wherein the alkene is ethene and the polymer is polyethylene.
 8. The process according to claim 6, wherein the contacting is in a homogeneous liquid phase.
 9. The process according to claim 6, wherein the conditions include at least one of a pressure of about 5 to about 50 bar, or a temperature of about 40 to about 80° C.
 10. The process according to claim 6, further comprising shaping the polymer to provide an article.
 11. The catalyst composition of claim 1, wherein the ether catalyst modifier comprises tetrahydrofuran.
 12. The catalyst composition of claim 3, wherein a ratio of the number of MeAlO repeating units and the number of R³AlO repeating units is about 20:1 to about 1:1.
 13. The catalyst composition of claim 4, wherein a molar the ratio between the aluminoxane and the organic aluminium compound is about 1:5 to about 5:1.
 14. The catalyst composition of claim 5, wherein the organic aluminium 